Simple, transparent
pricing
Start for free, upgrade when you're ready to master system design.
Starter
No credit card required
- ✅ Basic System Design Topics
- ✅ Standard AI Feedback
- ✅ Voice + Whiteboard
Pro
For serious interview prep
- 🔥 Unlimited Credits
- 🔥 Priority AI Response
- 🔥 Advanced Topics & Scenarios
- 🔥 Detailed Score History
Everything included in Pro
One subscription, unlimited access
Unlimited Sessions
Practice as much as you need. No session limits, no waiting.
Priority AI Models
Access our smartest, fastest models for the most realistic 45-minute interviewer experience.
Advanced Analytics
Deep dive into your performance with detailed scoring based on industry-standard rubrics.
Industry-Standard Rubric
How You're Graded
Our AI evaluates you using the same criteria as top-tier tech companies. We cross-reference what you say against what you draw to ensure visual clarity and prevent hand-waving.
- 01Requirements Gathering: Ability to clarify scope, DAU, and read/write ratios.
- 02High-Level Design: Logical component choices and overall system architecture.
- 03Deep Dives: Ability to handle curveballs and justify trade-offs under pressure.
- 04Visual Consistency: Verifying mentioned components actually exist on your whiteboard.
Score Calibration
*Our "Ghost Architecture" penalty caps scores at 75 if you talk about components you didn't draw.
Frequently Asked Questions
What is a "Credit"?
1 credit equals 1 full 45-minute interview session, including the AI voice sparring, real-time whiteboard tracking, and a detailed post-game analysis.
Can I cancel anytime?
Yes, you can cancel your subscription instantly from your account settings. You'll keep access until the end of your billing period.
What happens to my data?
Your session history and feedback are preserved even if you downgrade to the free plan. We do not use your private interview data to train our AI.
Is there a student discount?
We offer special challenges and access for partner universities like MIT and Harvard. Use your university email to check for active promotions.